1. Field of the Invention
This invention relates to a parking brake operating device for automotive brakes. More particularly, it relates to an automotive parking brake operating device which is used for those brakes of cargo trucks whose brake cable must be pulled over a great length to assure sufficient braking force. It also relates to a parking brake operating device in which a rotating member having a brake cable winding portion cooperates with a plurality of locking mechanisms, and in which, when the brake handle is operated, an operating rod and a cam of at least one of the locking mechanisms move with the brake handle, whereby the brake handle is repeatedly operated to wind the necessary length of the brake cable so as to firmly lock the parking brake.
2. Description of the Prior Art
Generally, many conventional cargo trucks employ a center brake type parking brake. There is a growing tendency in recent years for incorporation of the parking brake function into a leading trailing brake (referred to as "LT brake" hereinafter) in order to reduce the cost of the parking brake and to cope with the thermal load caused when the dynamic parking is effected.
However, in the parking brake incorporated into the LT brake, the length of the brake cable that must be pulled to ensure sufficient braking force is long compared to the conventional center brake type, so that it is extremely disadvantageous to apply a conventional single-stroke type parking brake operating device to the LT brake. This is because the single-stroke type operating device cannot pull the required length of cable with one stroke and, to meet this requirement, the stroke of the brake handle necessarily becomes long and it would therefore be difficult to operate the device.